It has heretofore been proposed to provide a suction catheter for removing undesired particles, mucous, blood or similar debris from a cavity in the human body, such catheters usually comprising an elongated, flexible tube having one end connectable to a source of vacuum, the other end forming an insertable tip with a suction inlet therein and an opening to atmosphere near the proximal end which can be selectively closed by the thumb of the surgeon to seal the tube and apply suction.
One type of suction catheter is disclosed in U.S. Pat. No. 3,375,828 to Sheridan of Apr. 2, 1968 in which a rolled up sleeve can be unrolled over the airway control aperture to apply suction in the nose, mouth, pharynx, trachea, bronchi, or other cavity in the body of a patient.
In U.S. Pat. No. 3,982,540 to Ross of Sept. 28, 1976 a multilumen tube is disclosed in which there are a plurality of spaced suction apertures in the outside wall of the negative pressure tube and a plurality of spaced positive pressure apertures, each located behind a suction aperture, to dislodge particles blocking the suction apertures.
In U.S. Pat. No. 4,014,333 to McIntyre of Mar. 29, 1977, a combined suction and irrigation instrument is disclosed for use in opthalmic surgery wherein an inner and an outer tube of straight rigid material are provided in fixed relationship, the suction tip of the inner tube projecting beyond the irrigation tip of the outer tube, so that the debris-receiving, suction inlet opening is in front of, and beyond the annular pressurized irrigation outlet opening.
The above mentioned Ross and McIntyre patents, which disclose combined suction and irrigation, both teach the placement of the pressurized liquid outlets in rear of the suction inlets and both teach a fixed relationship of the irrigation tube and the suction tube, so that the irrigation tube cannot be easily and quickly removed.
In addition to the above patents, there is a line of road vacuum cleaning apparatus, typified in the patents listed below in which there are debris-receiving inlets and/or suction inlets combined with air pressure outlets for dislodging trash, but these patents also teach placing the air outlet in rear of, or flush with, the suction, or debris-receiving, inlet.
U.S. Pat. No. 2,990,019 to Finn of June 27, 1961
U.S. Pat. No. 3,221,358 to Dickson of Dec. 7, 1965
U.S. Pat. No. 3,447,188 to Maasbery of June 3, 1969